Recently I tried to install Gentoo on Sun Blade 150 (sparc / sun4u processor). Almost everything went smoothly up to the point when I wanted to configure X. This box has Sun DP17MO monitor and on-board ATI Rage XL video card with 8MB RAM. This combination refused to work nicely in xorg-6.8.2-r1. Instead the monitor was still displaying a floating "Sync. out of range" message. A similar problem has been already described here: http://lists.debian.org/debian-x/2004/06/msg00146.html

After checking the logs I've found that indeed the card reference clock has been detected incorrectly. It was only 14.318 MHz, while it should be 28.636 MHz (as in most x86-based installations). So, adding a ReferenceClock option really helped to solve this problem: